1. Field of the Invention
This invention relates to an improved ladder attachment apparatus which facilitates the lifting of objects and machinery from the ground and other surfaces to the roof of a building or other elevated position, and more specifically relates to a stabilized power winch system and assembly which can be used in combination and conjunction with a number of commercially available ladders to provide a stronger, more stabilized ability to position a ladder for more convenient lifting of objects ranging in weight up to considerably heavier objects for the purpose of transporting them to the roof of a building or other surface.
2. Background Information
Various types of ladder hoists, ladder hoist attachments, and ladder attachments facilitating the lifting of an operator or an object have been known or marketed for use by painting, maintenance and construction personnel. Typical of these inventions are U.S. Pat. Nos. 4,598,795; 4,128,228; 3,430,734; 3,428,145; 3,115,211; 3,074,508; 2,459,621; 2,405,505; 1,386,511; 800,896 and 156,541; which were located during the process of a patent search. Copies of all patents cited are enclosed pursuant to 37 C.F.R. .sctn..sctn.1.97-1.99.
U.S. Pat. No. 4,598,795 issued to Larson relates to a ladder hoist attachment having a combination of a boom and a prop which is used with a conventional ladder, as they existed in 1985, to hoist loads preferably on to the roof of a building in the construction, roofing or air-conditioning trades. The boom assembly of Larson is provided with a number of feet that are designed to removably secure the boom to a rung of a conventional ladder being utilized. The boom extends horizontally over the top rung of the ladder with a number of braces connecting the feet and the boom. The boom assembly has a forward most brace which rests against the top rung of the ladder to provide support for the boom. A winch or pulley is suspended from the end of the boom to facilitate the lifting of a load. This invention discloses a hand operated winch or pulley system which is operated by the worker from the top of the building. The prop is provided with one end to be removably secured to one of the ladder rungs below the boom assembly. The other end of the prop has a vertical step to engage or catch only a square edge of a roof to hold the ladder away from this portion of the roof.
The Larson patent does not disclose or solve the problem of extending a ladder away from a building having a sloped roof. Nor does the Larson invention provide the other structural and functional advantages which exist in the present invention.
Specifically, Larson does not disclose or claim the mounting plate means and the winch/power means of the present invention. The ladder extension means of the present invention is structurally and functionally distinguishable from the prop of Larson, and will facilitate the ability to extend a ladder away from a sloped roof as well as a flat or square roof. Additionally, Larson does not utilize a ladder stabilization means, as the present invention does, to facilitate the safe positioning of the base of a ladder, and the lifting of substantially heavier objects to different elevated surfaces.
U.S. Pat. No. 4,128,228 issued to Ziegelmann on Dec. 5, 1978 discloses an extension ladder hoist having a hoist for raising and lowering articles from one elevation to another. It is designed to work in combination with a ladder which provides one portion of the necessary support for the apparatus. Ziegelmann is distinguishably different from the present invention structurally and functionally, and does not disclose or attempt to solve the problem of ladder base stability or the lifting of heavier objects. The Ziegelmann apparatus has no lower ladder stabilization means whatsoever. Ziegelmann further appears to disclose an apparatus which must be securely and fixedly attached to a roof portion., therefore, providing a positional disposition where its top support plate provides questionable stability with regard to the top of the ladder. Further, the means of interposing its frame member between the ladder and the roof is not disclosed clearly or specifically claimed in Ziegelmann.
U.S. Pat. No. 3,115,211 issued to Ostrander on Dec. 24, 1963 discloses a ladder hoist which is in part removably mounted as a carriage on the side rails of a conventional ladder, as they existed in 1961. This invention utilizes a spacing attachment 88 which is interposed between an upper rung of the ladder and a flat wall portion on the side of a building. Ostrander utilizes no mounting plate means as such, and employs no lower ladder stabilization means. Additionally, the spacing attachment 88 is structurally and functionally distinguishable from the ladder extension means of the present invention.
It should be emphasized that none of the prior art patent references cited disclose or claim directly or by equivalence an apparatus which has in combination the following elements: (1) mounting plate means; (2) winch/power means; (3) pulley block plate means; (4) ladder extension means and (5) lower ladder stabilization means. Additionally, the prior art is distinguishable structurally and functionally on an element-by-element basis.
None of the references specifically illustrates the present invention. Nor is the present invention obvious in view of any of the prior art references. In addition, all of the prior art heretofore known suffer from a number of disadvantages:
(a) The prior art devices do not address the problem of properly and securely stabilizing the lower or base portion of a conventional ladder so that the base will not slip in any direction under the substantially increased weight imposed on the ladder by lifting heavier objects, equipment and machinery, or the weight of a climbing person hand-carrying or lifting a heavy object or piece of equipment while climbing up or down the ladder. Additionally, the designs utilized in the prior art devices do not adequately address the problem of stabilizing the positioning of elements used to hoist or lift objects on the ladder itself.
(b) The prior art devices are not specifically designed to address the problem of providing a safe, removeable extension means having a safety slot system for holding an upper rung of a ladder in safe, supportable position while safely extending the ladder a comfortable, workable distance from a sloped or flat roof or surface to continently permit the passage of an object being raised or lowered in relation to the roof or surface.
(c) The prior art devices do not adequately solve the problem of providing safe, stable upper and lower support of a ladder when a worker is attempting to carry a heavy object up a ladder by hand from a ground surface to an elevated surface such as the top of a building or roof area.
(d) The prior art hoist systems do not address the problem of ladder base stabilization or stabilization of a hoist or lifting means.
(e) It is yet a further disadvantage of the prior art hoist devices that they do not adequately address the problem of safely being attached and secured to a conventional ladder, or being properly balanced relative and in combination with its relationship to the ladder.
(f) Additionally, the prior art devices do not adequately address the problem of being easily removeable from a conventional ladder and being conveniently transported to a work site.
(g) The prior art devices are further not specifically designed to safely lift heavier than average objects and equipment to elevated heights, or between spaced surfaces.
(h) Additionally, the prior art devices suffer from complexity of structure and movement of many moving parts to attempt to solve the problems related to lifting objects and heavy equipment.
(i) Further disadvantages in the structure and function of the prior art devices exist in their failure to adequately utilize advantageous support and lifting angles in the placement of support members and the lifting of objects.
(j) An additional disadvantage of the prior art is the absence functionally in the prior art devices of safely pivotable positioning of a ladder prop member or means to adequately facilitate the placement, support and secondary positioning of a ladder prop to adjust to changing work conditions such as allowing objects of different sizes to be lifted by a safe route between the wall or roof surface and the ladder positioned against it.
(k) Yet another disadvantage of the prior art devices is that they are not easily adoptable to the many diverse types of conventional ladders on the market, and often require specially constructed, non-conventional ladders and/or tracking or rail mechanisms.
(l) Additionally, the prior art hoist devices are not easily set up for operation by one person, but often require more than one person to facilitate operation in a work area.
(m) A further disadvantage of the prior art is the fact that these hoist devices are not adequately suited for a work person to remain on the ladder while an object is being lifted.
These and other disadvantages of the prior art will become apparent in reviewing the remainder of the present specification and the drawings.
Accordingly, it is an object of the present invention to provide a power winch system that has a means of securely stabilizing the lower or base portion of a conventional ladder so as to prevent the movement or slippage of this area when power lifting heavier objects or when equipment is carried up a ladder by hand.
It is a further object of the invention to have more stable positioning of each of its elements for lifting heavier objects; and to provide a safe removeable extension means which is provided with a safety slot backup system for holding the upper rung of a conventional ladder in supportable position while safely extending the ladder a distance from a sloped or flat roof surface to conveniently permit the passage of an object being raised between the ladder and the side of a building.
It is a further object of the present invention to provide both stable upper and lower support for a ladder during heavy power lifting, and when a worker is attempting to carry an object up a ladder by hand.
It is yet a further object of this invention to provide upper and lower hoist elements that are safely attached and secured to a conventional ladder., and which are easily removeable from the ladder and conveniently stored and transported to and from a work site.
It is a further object to provide a stabilized ladder power winch system which is specifically adopted and designed to safely lift heavier than average, and very heavy, objects and equipment from base (or ladder installation) surfaces to elevated surfaces, supporting and lifting such objects between a conventional ladder and the side or lateral surface of a building or other elevated structure.
Further objects of the invention are to provide a power winch system whose elements retain simplicity of structure and movement, and which utilize more advantageous support and lifting angles in the placement of its support elements and the lifting of objects and equipment.
An additional object of the present invention is to provide a ladder extension means which is safely pivotable to advantageously better facilitate the positioning, support and secondary positioning of a ladder extension member, so as to enable a worker faced with changing work conditions to adjust the position of a ladder or the space or distance between a ladder and the side surface of a building, for allowing objects of larger size to be lifted therebetween, and to the roof of a building.
Yet another object of the invention is to provide a power hoist system which is easily adopted and fitted to a number of diverse types of conventional ladders, without special additional equipment or changes to the structure of a conventional ladder itself.
An additional object of the present invention is to provide a power winch system which is easily set up and operated by one person, and which provides the unique ability for a person to remain on a ladder while an object is being lifted for partial periods of time should changing work conditions require this.